1. Field of the Invention
The present invention relates to a photosensitive composition which reacts upon irradiation with an actinic ray or a radiation to change in property, a compound for use in the photosensitive composition, and a method of pattern formation with the photosensitive composition. More particularly, the invention relates to a photosensitive composition for use in the production of semiconductors, e.g., IC's, production of circuit boards for liquid crystals, thermal heads, etc., and other photofabrication processes and in other applications including lithographic printing plates and acid-curable compositions, and also to a compound for use in the photosensitive composition and a method of pattern formation with the photosensitive composition.
2. Description of the Related Art
A chemical amplification type resist composition is a material for pattern formation which functions by the following mechanism. Upon irradiation with a radiation such as, e.g., far ultraviolet rays, the composition generates an acid in the exposed areas and undergoes a reaction catalyzed by this acid. As a result, the composition comes to have a difference in solubility in a developing solution between the areas irradiated with the actinic radiation and the unirradiated areas to thereby form a pattern on the substrate.
In the case where a KrF excimer laser is employed as an exposure light source, a resin having a poly(hydroxystyrene) backbone which shows reduced absorption mainly in a 248-nm region, is used as the main component. Because of this, the composition has high sensitivity and forms satisfactory patterns with high resolution. It is hence a better system as compared with the naphthoquinonediazide/novolak resin system heretofore in use.
On the other hand, in the case where a light source having a shorter wavelength, e.g., an ArF excimer laser (193 nm), is used as an exposure light source, even the chemical amplification type system has been insufficient because compounds having aromatic groups intrinsically show considerable absorption in a 193-nm region.
Because of this, resists for an ArF excimer laser which contain a resin having an alicyclic hydrocarbon structure have been developed.
As photo-acid generators have been used compounds which generate a perfluoroalkanesulfonic acid such as trifluoromethanesulfonic acid or nonafluorobutanesulfonic acid. Furthermore, photosensitive compositions containing a compound which generates a specific sulfonic acid (see, for example, JP-A-2003-140332, European Patent Application Publication No. 1,270,553 and International Publication No. 02/042845, pamphlet) and photosensitive compositions containing a compound which generates a specific sulfonic acid and a resin which decomposes by the action of an acid to come to have enhanced solubility in an alkaline developer (see, for example, JP-A-2002-131897 and JP-A-2002-214774) have been proposed.
US Patent Application, Laid-open No. 2004/0087690 specification also describes a photo-acid generator containing a sulfonic acid anion having a fluorinated hydrocarbon group.
However, those compositions are still insufficient in many points and various improvements are desired. For example, there is a desire for the prevention of pattern falling and diminution of line edge roughness.